Noncontact ink jet printers control print cartridges inserted into the printers to eject droplets of ink from a plurality of ejection nozzles formed in printheads of the cartridges. Printheads are commonly formed using thin/thick film and integrated circuit technologies including etching and other well known processing techniques to operate on substrates made, for example, of silicon. The nozzles extend from nozzle chambers associated with heaters which, when activated, vaporize a portion of ink in the chambers to eject ink drops from the nozzles.
Manufacturing tolerances lead to mechanical and electrical variations in the printheads/print cartridges that affect formation of ink drops. Variations include differences in ink channel dimensions that affect ink flow, differences in nozzle chamber dimensions that affect vapor bubble formation, differences in nozzle dimensions that affect drop shape and velocity, and differences in heater and heater connection resistances that affect voltage requirements for effective heater activation.
These mechanical and electrical printhead/print cartridge variations can result in nonuniform ink ejection across printheads of print cartridges. The problems of nonuniform ink ejection due to such variations are increased as the size of the printhead assemblies increase to provide wider swath widths and faster print speeds. Accordingly, there is a need to compensate for mechanical and electrical variations to improve the uniformity of drops ejected from print cartridges and thereby the print quality produced by printers using the print cartridges. Preferably, the print cartridges would be individually characterized to enable printers using the cartridges to customize control of the cartridges based on their individual characteristics and thereby improve uniformity of ink ejection from the cartridges.